ML20085L712

AO 50-267/75/4:on 750125,tritium Leaked from Secondary Closure of Refueling Region 1.Cause Will Be Determined When Vessel Pressure Dropped to Atmospheric or Below

ML20085L712
Person / Time
Site:	Fort Saint Vrain
Issue date:	02/14/1975
From:	Brey H PUBLIC SERVICE CO. OF COLORADO
To:	Howard E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20085L708	List: ML20085L707 ML20085L712
References
AO-50-267-75-4, NUDOCS 8311020368
Download: ML20085L712 (4)

Text

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                          ,                ..q[     j /          February 14, 1975
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                                      'h          O MIJr Mr. E. Morris Howard, Director Region IV, Office of Inspection and Enforcement 611 Ryan Plaza Drive - Suite 1000 l

Arlington, Tecas 76012 l Ref: Facility Operating License No. DPR Docket No. 50-267

Dear Mr. Howard:

Enclosed please find a copy of Abnormal Occurrence Report No. 50-267/75/4, submitted per the requirements of the Technical Specifications. Very truly yours,

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H. Larry Brey Superintendent-Operations Fort St. Vrain Nuclear Generating Station HLB:11 cc: Mr. Angelo Giambusso I" 8311020368 750314 PDR ADOCK 05000267 S PDR WPY SENT REGION 3 3007

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   . es E '                                                                                                   1 REPORT DATE:           February 5, 1975                                  .                            ABNORMAL OCCURRENCE OCCURRENCE DATE: January 25, 1975 FORT ST. VRAIN NUCLEAR GENERATING STATION PUBLIC SERVICE COMPANY OF COLORADO P. O. BOX 361                                                                                            i PLATTEVILLE, COLORADO                    80651 REPORT No. 50-267/75/4 Preliminary
                                                                                                                                                      .             l IDENTIFICATION OF OCCURRENCE:

When the secondary closure of refueling region #1 was loosened, Health Physics personnel detected Tritium leaking from the penetration, indicating a possible breach of the primary closure. Such'a breach would be a violation of paragraph 2.1.c of the Technical Specifications. CO:,"JITICNS I'RIOR TO OCCURRENCE: Steady State Power

• Routine Shutdown Hot Shutdown Routine Load Change O

X Cold Shutdown Other (specify) Refueling Shutdown Routine Startup The major parameters at the time of the event were as follows: Power Rtr 0 -MWth Elect. / 0 MVe Secondary Coolant Pressure N/A psig . Temperature N/A *F Flow N/A #/hr.

               .. Primary Coolant                      Pressure                                          '87              psig                           -

Temperature- 275- *F-Core Inlet 260 *F Core Outlet 0 Flow Less than 100.000 f/hr. .

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   .v Note:      Average core temperature is lower than core inlet because the Primary Coolant was being heated by passing steam through the reheat section of the steam generators.

DESCRIPTION OF OCCURRENCE: i Testing of the operability of Reserve Shutdown hoppers after nodifying the pressurizing supply lines to a " soft scat" type revealed the inability to trip the test switch in No. 1 CRD with 35# pressure. It was decided to check the pressurizing line in No.1 refueling penetration. The secondary closure plate on refueling penetration #1 was being removed to examine the Reserve Shutdown pressurizing line. Routine Health Physics coverage established that tritium levels around the secondary seal went to

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approximately twice background when the cover hold down bolts were loosened. This indicated a possible co=muncation of the penetration interspace with the primary coolant (i.e. . , a breach of the primary closure) . The secondary cover plate was retightened to stop any outleakage and Tritium levels dropped to the previous background level. The leak rate through the secondary cover plate was of short duration, of unknown amount. The leak, if any, throuch the primary closure, is less than the allowable, for the group,as shown on flow gaugua. APPARENT CAUSE OF OCCURRENCE: Design Unusual Service Cond. Including Environment Manufacture X Component Failure Installation /Const. other (specify) Operator Procedure If a breach does, in fact, exist, one of the boundaries of the primary closure has failed. ANALYSIS OF . OCCURRENCE: . Analysis cannot be completed until vessel pressure is dropped to atmospheric or below so the secondary closure can be removed, 'and ~ the primary closure . boundaries can be examined. . The quantity of primary coolant released'although minimal,~is unknown. Background reading before loosening the secondary cover plate was 0.9 pCi per cubic meter. On loosening the plate the reading (with the probe right at the ! secondary closure surface) rose to 1.8 uCi per meter.

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                                                                                      -            Pege threc CORRECTIVE ACTION:

Not determined at this time. FAILURE DATA / i SIMILIAR REPORTED OCCURRENCES: None PROGRAMMATIC IMPACT: None expected due to concurrent maintenance requirements. *

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CODE IMPACT: None RECOMMENDED: APPROVED: >

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Frank Mathie D lw < d.4'~' F/ederic E. Swart Superintendent-Maintenance 6uperintendent Nuclear Production Fort St. Vrain Nuclear Public Service Company Generating Station of Colorado

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